Rust protection and distance device for reinforcing rod chairs



Jan. 13, 1970 .A. B1ABERG 3,488,907

RUST PROTECTION ANDDISTANCE DEVICE FOR REINFORCING ROD CHAIRS Filed Dec.14, 1967' I N VEN TOR A/zde/s' Berfz/ Abe/' United States Patent US. Cl.52309 4 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates to arust protection and distance device for covering ends of reinforcing rodchair feet in concrete structures which, when pouring the concrete, areto rest against a mould. The device which according to the disclosure ismade from plastics such as, polyethylenes, polypropylenes,polyvinylchlorides and polyamides constitutes a socket to be applied tothe ends of the chair feet, the socket comprising a sleeve which is openat one end and closed at the other by a bottom portion. The cavity ofthe sleeve, has adjacent the bottom, a smaller cross section than thecross section of remaining portions of the cavity nearer to said openend. The sleeve has at least two mutually remote distance meansprotruding radially from the outer surface of the sleeve in at least onecommon direction radially of the sleeve.

BACKGROUND OF THE INVENTION The invention relates to an improved rustprotection and distance device, in particular for concretereinforcements. The purpose of such distance devices is to maintainhorizontally disposed reinforcing rods at a predetermined distance fromthe form when pouring floors, slabs or the like, and a rust protectionand distance socket constituting part of such distance device.

When mounting reinforcements for concrete constructions prior to pouringthe concrete, and in particular when it is a question of heavyreinforcements, so called chairs made from round-iron pieces, the endsof which are bent so as to constitute feet defining a support of thechairs to provide a desired stability and surface of contact with theform, are used to support reinforcing rods at a desired distance fromthe form. The ends of the round-iron pieces which constitute the feet ofthe chairs usually cause certain inconveniences as regards the finalconcrete construction, firstly due to the fact that wounds may appear inthe concrete surface, secondly, due to the fact that the ends are apt toconstitute an entrance for rust attacks on the reinforcement.

It is an object of my invention to provide a device 'by which saidinconveniences are eliminated in a substantial degree and, to this end,relates to a rust protection and distance device constituting a socketfor ends of rods supported by a concrete form when pouring the concrete,said device having properties as defined in one or more of the appendedclaims.

SUMMARY OF THE INVENTION According to the invention a rust protectionand distance device of the kind described is substantially characterizedby the fact that said device comprises a sleeve which is open at one endand closed at the other by a bottom portion, the cavity of the sleevehaving adjacent the bottom a smaller cross section than the crosssection of remaining portions of the cavity nearer to said open end,said sleeve having at least two mutually remote distance meansprotruding radially from the outer surface 3,488,907 Patented Jan. 13,197( thereof in at least one common direction radially of thl sleeveaxis.

Plastic materials suitable for the purpose are, by wet: of example,polyethylenes, polypropylenes, polyvinyl chlorides, polyamides.

-With a device as defined the result is attained, that ill! end of therod constituting the chair is protected agains influences of humidity atthe concrete surface, the contac with the concrete form when pouringbeing present at 2 number of restricted areas and by the intermediary of2 material which is experienced to give rise to no or only insignificantmarks in the poured concrete. When the socket cavity has a conical shapeor has otherwise 2 somewhat larger diameter than the rod end introducedinto the cavity, there will be an annular space between the socket andthe rod, which, when tamping the concrete, is partially filled withconcrete and protects the portion of the round-iron against rusting byinfluence oi humidity, which would otherwise possibly come into contactwith the iron via a relatively short creep length.

Other objects, features and advantages of my invention will becomeapparent from the following description with reference to the drawings,in which:

' BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of anembodiment of my invention and constituting a socket to be applied tothe end of a round-iron rod bent to constitute a chair for areinforcement rod, for instance,

DESCRIPTION OF A PREFERRED EMBODIMENT In FIGS. 1 and 2, the rustprotection and distance device comprises a frusto-conical sleeve 1, thewider end of which is open and the smaller end of which is closed by abottom 2, the device constituting a socket to be placed over the end ofa rod of appropriate dimension. The slope of the walls of the sleeve canbe rather small and need not be as large as illustrated in FIGS. 1 and 3for illustrative purpose. With slope of the walls toward the axis of thesleeve as small as 0.2, corresponding to a difference in diameter ofabout 0.5 mm. for a length of the sleeve of 10 cm., the sleeve will beeasily applicable to the end of a rod of appropriate dimension to beheld thereon by coaction between the walls of the sleeve and the rodsadjacent the closed ends of the sleeve. Chairs of this kind forreinforcement irons or other bar-shaped components to be enclosed by thepoured concrete, are usually made from round-iron having a diameter ofbetween 4 and 10 mm.

A number of distance means extend radially of the external surface ofthe sleeve. As illustrated in FIGS. 1 and 2, said distance meansconstitute annuluses 3, extending radially in the peripheral directionof the sleeve. Said rings protrude a distance of at least 0.5 andpreferably 1-3 mm. and more from the external surface 4 of the sleeve.When the protection devices are placed onto'the legs of a chair asillustrated in FIG. 2 said rings as well constitute means for preventinghumidity from migrating along the sleeves toward the reinforcement ironthrough the concrete along the legs of the chair.

3 lhe round-iron piece 5 is bent to a shape so as to convute a chairhaving two legs 6 and an intermediary vered portion 7 to support areinforcement rod, the legs ling ends 8 which are bent out laterally andin opposite ections so as to define a support area of the chair on theWild. The ends 8 have a tight fit in the sleeve at and acent the bottom2 thereof, so that the sleeve is sefely held onto the chair. Due to theconical shape of sleeve, an annular space 10 is present between the eveand the round-iron 5 adjacent the open end 9 of the eve, said annularspace to be filled with finely divided lcrete during tamping, saidconcrete providing for an reased creep length for humidity from theconcrete "face to the portion of the round-iron inserted into the eveand not covered by a concrete layer protecting it ainst corrosion. FIG.3 shows a modification of the protecting means lstrated in FIG. 1. Inthis embodiment, distance memrs 11 extend radially of the sleeve onlyalong one side reof. In this embodiment the protection against creephumidity along the external wall of the sleeve is less .cient than withthe embodiment according to FIG. 1. [n the embodiment illustrated inFIG. 4, the cavity of a sleeve has a cylindrical shape and has aconstriction iacent the bottom 2 constituted by a rounded cam 12 to ldthe protection device attached to the round-iron and one of theannuluses lateral holes 13 for nails to temrarily hold the chairattached to a form before and ring pouring, the nails being removedafter removal of a form by pulling them out of the plastic socket. Whilethis invention has been described with respect to :cific examplesthereof, it should not be construed as ing limited thereto. Variousmodifications and substituns will be obvious to everyone skilled in theart and 1 be made without departing from the scope of this Iention. Iclaim: 7 1. .A chair for supporting reinforcing bars above thebstantially horizontal surface of a form comprising a rod :rnent formedinto an inverted U-shaped structure havg a saddle for supporting areinforcing bar, two bent mgate foot portions laterally spaced from eachother id extending horizontally away from the plane of the U- apedportion of said structure in opposite directions and apted to overliesaid form surface, and a rust protector r each foot portion comprisingan integral molded prodt made of a synthetic resin having a body portionin the .4 form of an elongate hollow sleeve which is closed at one end,and a plurality of projections extending downwardly from the outersurface of said body portion for spacing said body portion above saidhorizontal form surface, the interior surface of said sleeve beingshaped to provide a gripping engagement with said elongate foot portionat a point remote from the open end of said sleeve, said open end beingof a diameter sufiiciently greater than the diameter of said footportion as to receive concrete mix and permit the formation of aconcrete plug to prevent entry of water into the space between thesurface of said elongate foot portion and the interior surface of saidsleeve, at least two of the projections of each rust protector beingremotely spaced from each other to provide a stable three point supportfor said chair comprising the two remotely spaced projections of therust protector of one foot portion and one projection of the laterallyspaced rust protector of the other foot portion.

2. A rust protector as claimed in claim 1 in which said interior surfaceis tapered.

3. A rust protector as claimed in claim 1 in which said interior surfaceis provided with an annular constricted portion located close to saidclosed end but spaced therefrom.

4. A rust protector as claimed in claim 1 in which said projections arein the form of annular flanges surrounding said body portion.

References Cited UNITED STATES PATENTS 3,132,448 5/1964 Phillips et al52689 2,305,979 12/1942 Mitchell 52396 X 3,289,378 12/1966 Carroll5268'8 3,348,347 10/1967 Berry 52309 FOREIGN PATENTS 338,587 7/1959Switzerland.

963,741 7/1964 Great Britain.

OTHER REFERENCES 293,077, July 1965, Netherlands, printed applicationCarroll.

ALFRED C. PERHAM, Primary Examiner U.S. Cl. X.R. 52-689

